# Module 2 – Foundations of physics

## The rules for determining percentage uncertaintiesThe rules for determining percentage uncertainties

A key assessment objective of the evaluative tasks is going to be determining the final uncertainty in a quantity. Here are some useful rules:

We can determine the uncertainty in the gradient by drawing lines of maximum and minimum gradients through their scattered data points. What happens when there is little scatter of the data points? This is when we draw error bars. Error bars show the range a point is...

## Determining the uncertainty in the y-intercept using maximum and minimum gradientsDetermining the uncertainty in the y-intercept using maximum and minimum gradients

We can also determine the uncertainty in the y-intercept by using lines of maximum and/or minimum gradients through their scattered data points. What happens when there is little scatter of the data points? This is again when we can draw error bars. a. Error bars may...

## Percentage differencePercentage difference

You may be asked to determine the percentage difference between experimental values and accepted values. ‘Experimental values’ are those that are derived from measurement or calculation, whereas ‘accepted’ or ‘theoretical’ values are values that are accepted by the...

## Scalars and VectorsScalars and Vectors

A Scalar quantity is a quantity which only has magnitude. Some examples of Scalar quantities are: o Mass o Time o Temperature o Length o Speed o Energy >A Vector quantity is a quantity that has both magnitude and direction. Some examples of Vector quantities are: o...

## UncertaintiesUncertainties

Absolute Uncertainties: The absolute uncertainty (usually called absolute error - but "error" connotes "mistake", and these are NOT mistakes) is the size of the range of values in which the "true value" of the measurement probably lies >If single readings have been...

## Physical QuantitiesPhysical Quantities

Physical quantities have a numerical value and a unit. These are physical quantities that can be quantified: Examples are o Mass o Length o Temperature o Time  Estimates of physical units can be made.